1. Technical Field
The present invention relates to a temperature control device and a turbo-molecular pump.
2. Background Art
A turbo-molecular pump has been used as an exhaust pump for various semiconductor manufacturing devices. However, when exhausting is performed in, e.g., an etching process, a reactive product is accumulated in the pump. In particular, the reactive product tends to be accumulated in a gas flow path on a pump downstream side. When the reactive product is accumulated to such an extent that a clearance between a rotor and a stator is filled with the accumulated substance, various troubles are caused. For example, the rotor is fixed to the stator, and as a result, becomes unable to rotate. In addition, a rotor blade(s) comes into contact with a stator side, and as a result, is damaged. Thus, a turbo-molecular pump configured such that accumulation of a reactive product is reduced by heating of a pump base portion has been known (see, e.g., Patent Literature 1 (JP-A-10-266991)).
The turbo-molecular pump described in Patent Literature 1 includes a base temperature setting unit configured to set a target temperature of the base portion based on the temperature of the rotary blade obtained by a rotary blade temperature detection unit, a temperature difference calculation unit configured to calculate a difference between the target temperature set by the base temperature setting unit and an actual temperature measured at the base portion, and a temperature control unit configured to control heating or cooling of the base portion based on an output signal of the temperature difference calculation unit. For preventing an abnormal temperature of the rotary blade when accumulation of the product is prevented by heating of the base portion, the target temperature of the base portion is set based on the temperature of the rotary blade obtained by the rotary blade temperature detection unit. In this manner, the rotary blade is protected while accumulation of the reactive product is prevented.
However, even when the target temperature of the base portion is set such that the abnormal temperature of the rotary blade is prevented, it is difficult to completely prevent accumulation of the reactive product, and accumulation of the reactive product cannot be avoided. For these reasons, the amount of accumulation of the reactive product increases as a pump operation time proceeds. Eventually, the problem of fixing the rotor to the stator with the reactive product is caused.